Stanly Hiller made a prototype that flew. It had a small ramjet on the tip of each of the 2 rotor blades. because a ramjet is amazingly simple, he had this plan to make small inexpensive ramjet powered helicoptors. He could sell these for about $ 5000 dollars, and in the future everyone could own a little helicopter that he would keep in his garage and he would use it to get to work.